climate

Category: climate

River Piracy sounds like an exotic form of stream based pillage and plunder, but rather refers to the reorientation of stream flow from one channel to another. Also known as stream capture, the causes vary, and include tectonics shifts which changes slope, natural dams (landslide or ice), headward and lateral erosion, karst topography, and glacial retreat. Notable ice dams have diverted rivers, of note is the River Thames, which was shifted 450,000 years ago cause it to

A recent set of stories about the Slims River in the Yukon territory illustrates the last of these points, where the retreat of the Kaskawulsh glacier and it’s shift from the Slims River to the northwest and into the adjacent Kaskawulsh River to the southeast. The phenomenon isn’t uncommon, but the pace in which this ‘theft’ occurred is notable: “Such a transformation has occurred numerous times throughout the planet’s geological history – often due to gradual erosion or the movement of a fault – but has never been observed to occur as suddenly, happening over just a few days in May 2016. ‘Geologists have seen [evidence of] river piracy before, but nobody to our knowledge has documented it actually happening [within] our lifetimes,’ explains Shugar, Assistant Professor of Geoscience at the University of Washington, Tacoma.” The image below shows the “aerial view of the ice canyon that now carries meltwater from the Kaskawulsh Glacier, seen here on the right, away from the Slims River and toward the Kaskawulsh River.”

A map of the area shows the relationship of the river and the shift, which short-circuited a longer path through the Kluane River into the Yukon River and eventually the Bering Sea, now connecting to the Alksek River and flowing into the Pacific Ocean. From a global perspective the flow doesn’t mean much, but on a local scale the impact is more acute.

“That water now flows into the Kaskawulsh River, a tributary of the Alsek, which runs southward to the Pacific. Following this route, it reaches the ocean some 1,330 kilometres away from where it would otherwise have ended up. Signs of the rerouting have been observed on both sides of the mountainous divide. Gauges on the Alsek River reveal that it experienced a record discharge last year. Because the river mostly flows through parks and protected lands, the increase has had no immediate human impact. On the Slims side, the effect of water loss is more obvious. Last summer, Kluane Lake dropped a full metre below its lowest recorded level for that time of year. The reduced inflow from the Slims spells a huge change for the 65-kilometre-long lake, with implications for nearby communities and visitors who access its waters for fishing and other activities.”

The quality of the Lake ecosystem is one issue also, as mentioned in the Guardian article “The river stolen by climate change”, quoting scientist Jim Best: “The dramatic switch was caused by the rapid retreat of the Kaskawulsh glacier – thanks to climate change – which caused the flow of the meltwater to be redirected, and prompts questions about the impact it could have on the surrounding Yukon territory. Best points out that while much of the southern part of the territory is ‘sparsely populated’, and therefore potential flooding caused by the extra water is unlikely to cause any ‘real human impacts’, the opposite issue could be a cause for concern further north. ‘If Kluane Lake levels go down,’ he predicts, ‘the lake could thus have no inflow and no exit flow, which would radically alter lake water nutrients and circulation, and this may impact on the lacustrine ecology. In addition, if the lake outlet were to dry up as a consequence, this river would be dry or far lower and thus the few habitations along it would be affected.’”

The dry valley left over, in this case the Slims River, is referred to as a wind gap, and scientists have discussed the potential issues erosion and dust storms. As noted in the CBC story, “Retreating Yukon glacier makes river disappear“, the river is: “…prone to dust storms. “It’s certainly not unusual to see rapid drainage changes in and around these glaciers. It’s a common situation,” Bond said. “Until vegetation really starts to stabilize that floodplain, it’s going to be a dusty place, I’d imagine … It will be a really interesting study to see how that floodplain evolves in the next ten years or so.”

A great kickoff lecture to the Waterlines class at the Burke Museum featured noted regional geologist and retired UW Professor Dr. Stan Chernicoff and his exploration of The Origins of Seattle’s Landscape. Having read a bit about the local geology over the years, and having experienced some specifics (particularly the glacial till in Seattle) in my work, I had a rudimentary understanding of the general picture in our region. Thanks to this lecture, and the philosophy that ‘dynamism is key and change is inevitable’ espoused by Chernicoff, I know a lot more and think about the region in new ways. From his lecture, I found some interesting links between the larger and longer scales of geologic time and it’s relevance to the Hidden Hydrology project.

His lecture loosely focused around the concept of changing Waterlines around the region, and organized his talk to be roughly chronological and covered a lot of ground – from 1.1 billion years into the past to 250 million years into the future. Much of the beginning conversation was looking back at the time when Seattle was not coastal but inland as part of the Rodinian Supercontinent (one of the pre-Pangean configurations) and the coastal accretion of lands from the final supercontinent (where to coast was originally at the MT/ID border), and the lands that were added over the past 150 million years (Okanogan Mountains, Cascade Mountains, San Juan Mountains and most recently the Olympia Mountains) through lands being drawn in through subduction. This means that Washington and Oregon are mere infants in the larger timescale, as Chernicoff mentions, compared with the larger geological history. The key diagram he showed here is the overlapping sections of the subduction zone in the Juan de Fuca plate and the location of between the Olympics and the Cascade Mountains, with the layers levels and timelines of geological traces over the past 50 million years..

The bit of trivia that Seattle is sitting atop the Olympic Mountains – as you can see by drawing a line through to the Crescent Basalts below us. The evolution from the last 40 million years in shaping the zone, through Volcanic mudflows (yeah, there was a volcano called Mt. Seattle somewhere near Issaquah) that left lahars 40 million years ago. This was followed by periods of inundation, and when the land was warm and swampy, which left the deposits of coal near Renton (an interesting Puget Sounds coal history where we ended up shipping to San Francisco). The marine heritage is also found in the prevalent Blakeley formation, which evolved from a shallow marine estuary from submarine landscape deposits 30 million years ago – and today one can still find fossil shells around many places in the Puget Sound.

There are some interesting facts that illuminate this history and dynamic story of change. First, while the larger geology set the stage and influences the form, the current lakes, and rivers were a product of the latest glacial period, which Cordilleran Ice Sheet covered the area and the Puget Lobe formed the shape of the current region. The glacier was around 3000 feet thick, which pushed the sound down almost 1000 feet, and created the depression that allowed water to flow in and formed the modern position of waters.

The rule of thumb is the thickness of depression will be 1/3 the thickness of the glacier. An interesting section (see right) showing how this cap of ice carved out Puget Sound nestled between the Olympic and Cascade Ranges – with linear scoured channels forming Hood Canal, Puget Sound, Lake Washington, Lake Sammamish, and created the terrains which Seattle occupied. These were all relatively north-south oriented which coincides with the intrusion and recession of the Puget Lobe. It is amazing to think of the larger glaciers in the Midwest, such as Minnesota, which were 3 miles thick and the impacts on that landscape, which for my knowledge, creates the rarity of the north-flowing Red River through where I went to college in Fargo, but also created the over 10,000 lakes that dot the region.

Second, is that because of the glaciation and recession, most of the hills in Seattle are glacial drumlins, (with the exception of West Seattle and Magnolia which are drift uplands). These hills were deposited upon glacial retreat, which gives them a distinctive steep north side and smoother south side, with alignment north-south as well as the long side corresponds to the direction of ice flow.

You see this in the larger hills in Seattle, as well as the creation of the individual creeks that are woven throughout the north section of the city. The topography carved these smaller drumlin shapes with drainages forming in the spaces at edges adjacent to lakes or between two hills. This formed unique geologic features like like Seward Park in the south section of Lake Washington.

A shapshot of the 1894 USGS Topo map shows the formation on Queen Anne (left) and Capitol Hill (right) with the steeper north edges, along with what is still showing the remnants of Denny Hill south before it and other topographic features were removed from the downtown area.

Third, the two smaller lakes in North Seattle, Bitter Lake and Haller Lake, are true kettle lakes, formed with glacial retreat. A hybrid of this is Green Lake, which also formed in the glacial retreat along with Lake Union and Lake Washington. Fourth, the glacial movement left a trail of glacial erratics all over the area, and I learned about one of the largest, the Wedgwood Rock, which originally was from miles north and now sits in NE Seattle. Definitely worth a field trip in the near future.

Fifth, the glacial deposition led to a preponderance of landslides, both with steep slopes, along with the layers of permeable Esperance Sand sitting atop a layer of Lawton Clay, which causes water to flow under the sand and create a slip zone (shown on right side of diagram below).

This is exacerbated by the copious winter rainfalls, which exacerbates the issue via critical liquifaction zones, which means“…a phenomenon whereby a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid.” Thus the landslides and earthquakes have shaped the hydrology over time, as valley configurations shift with deposition from streams but also are influenced by these disturbance regimes.

The Magnolia Neighborhood is one of those areas where it has overlapped with the danger of building on steep/unstable slopes, as shown here in a wikipedia image of a slide in 1954 on Perkins Lane, a relatively frequent occurrence in Seattle in particular areas over the years. Chernicoff’s hint: Don’t by a house there.

The final part of Chernicoff’s talk focused on the ‘Rise and Fall of Seattle’, with a theme that in our dynamic and ever-changing landscape, “we can’t get accustomed to where water is”. He mentions four factors that will influence the geology of Seattle, including Local Geology, Regional Tectonic Factors, Regional Isostatic Factors (i.e. glacial rebound), and Global Eustatic factors (i.e. sea level rise). This was interesting, as the local conditions were all creating conditions that led to raising lands and lower levels of water. For instance, the two local geological factors were river sedimentation and landslides, both of which add land particularly at the deltas of larger rivers, such as the Skagit and Nisqually Rivers. As Chernicoff put it, through those two factors, the entire Puget Sound is trying to fill itself in. The regional factors of tectonic activity are at work, with quakes occurring regularly, which can instantly change the shape of our landscape through an earthquake. A slower mechanism continues to shift land with raising land due to glacial rebound, bouncing slowly back from being compressed by glaciers thousands of years back.

Inevitably, for all the minor modifications of local and regional factors, the larger impact is, wait for it… yep, global change, in particular the shifts associated with climate change. The melting of remnant ice sheets in Greenland and Antarctica, warming causing the thermal expansion of water combined to create higher levels, and lead to massive impacts on the waterlines of Seattle and everywhere else. He showed as an example a slide of the map Islands of Seattle, a great project by Jeffrey Lin (inspired by the original Burrito Justice San Francisco Archipelago map.) which hypothesized on melting of all global ice, including the Antarctic, which would result in a 240′ rise in sea level, creating a very dramatic new waterline and hydrology for the City.

For Chernicoff, it wasn’t a question of whether this would this happen or not. His geologists time lens is long and he knows there will be large-scale global shifts. The question is yes, however, does the time scale of this inundation take 30 years, 500 years, 10000? It’s an interesting juxtaposition of of deep, long geological time coupled with the dangerous (but possibly earth saving) agency of humans in creating changes in rapidly shorter and shorter time scales, via anthropocentric factors. While we rightly fret over our fate and try to come up with solutions, the idea of dynamism and constant change is a good perspective. In the end, geological time and processes will, it seems, always win, if we’re around in another 250 million years we can experience a new shift to a larger subcontinent, as the Pacific is getting smaller and the Atlantic is getting bigger, so our coastal woes will change when we’re in the middle again. Full circle.

This has some implications, obviously for connecting history to present and future, as we are constantly chasing moving targets when we deal with landscape and water. How will these changes impact our understanding of historical conditions with current ones? At the short time scale we are considering, does it matter? Will rapid global and local changes impact our opportunities and ideas in which to engage with planning and design interventions? Something I’ve not ruminated on long enough to have ideas, but more to come. And more on Waterlines next week.

ADDENDA

As a follow up, a remembered this link from the Burke on Seattle’s Ghost Shorelines links there’s an interesting Waterlines video showing this evolution of the most recent 20,000 years of the sound – since the ice age.

Mexico City has been featured a few times recently in the New York Times, with a focus on some of the fascinating hydrological history and its implications to modern urban life. I was very ignorant of the specific characteristics of the city, and while I love Mexico have only had the chance to spend a long layover in Mexico City proper a few years back. I learned much in these few articles, with a desire to dig deeper as well.

The history of Mexico City as a city has many facets, but two emerge in this context. First is the concept that the city is built on a lake. This map shows the configuration of the area around 500 years ago, about the time the Spanish arrived in Mexico.

Tenochtitlán, the major urban center, was established in 1325, a larger island surrounded by smaller areas islands amidst Lake Texcoco – shown as the City of Mexico below. This aided in defense and provided agriculture using the chinampas, islands floated for growing crops.

The city was rapidly transformed via defeat and colonization:

Then the conquering Spaniards waged war against water, determined to subdue it. The Aztec system was foreign to them. They replaced the dikes and canals with streets and squares. They drained the lakes and cleared forestland, suffering flood after flood, including one that drowned the city for five straight years.

The article focuses on both this concept of geological transformation. The second part of the story of Mexico City is the Grand Canal. This infrastructural intervention was completed in the late 1800s, and ” a major feat of engineering and a symbol of civic pride: 29 miles long, with the ability to move tens of thousands of gallons of wastewater per second. It promised to solve the flooding and sewage problems that had plagued the city for centuries.”

The City being built on a lake has led to subsistence due to geological forces, and the need for drinking water has meant well drilling on a huge scale – both leading to elevations of the city being dramatically lowers. This makes gravity-based infrastructure like the Grand Canal a bit problematic, as they can no longer freely drain. The city, which occupied a metropolitan area of 30 square miles in 1950, now occupies closer to 3000 square miles, so and the almost 22 million inhabitants exert massive pressures on the land.

Some great interactive graphics from the NYT show the canal in the context of the ancient lake bed that sprawls through the region (see how this relates to the map above).

This plays out in the map below, which highlights the worst place of subsidence – the darkest red portions sinking around 9 inches per year.

[Click maps for larger views or check them out in the original article for overlay]

The problems, as mentioned, are based on some bad decision-making in urban planning back centuries ago. This have been exacerbated by climate change – meaning lack of drinking water for many and the potential to lead to health issues, mass migrations to other cities, or conflict, which will be played out around the globe. This example of non-coastal impacts of climate change is one of the most interesting aspects of the story, as much attention has been placed on sea-level rise but less on inland communities. “Mexico City — high in the mountains, in the center of the country — is a glaring example. The world has a lot invested in crowded capitals like this one, with vast numbers of people, huge economies and the stability of a hemisphere at risk.”

One way this phenomenon is visible is in the architecture, with subtle rolling building forms as seen below creating waves of differential settlement. An animation of the process shows the action creating this building form, due to differential layers of volcanic soils and clays, which drain and hold water at dramatically different rates.

What happens when the water is drawn down creates instability reflected in the constant sinking and retrofitting of buildings. Kimmelman explains the impacts: “Buildings here can resemble Cubist drawings, with slanting windows, wavy cornices and doors that no longer align with their frames. Pedestrians trudge up hills where the once flat lake bed has given way. The cathedral in the city’s central square, known as the Zócalo, famously sunken in spots during the last century, is a kind of fun house, with a leaning chapel and a bell tower into which stone wedges were inserted during construction to act more or less like matchbooks under the leg of a wobbly cafe table.”

Aside from the quirky buildings, there are major issues throughout the region, more pressing as climate change increases. Kimmelman mentions that “development has wiped out nearly every remaining trace of the original lakes, taxing the underground aquifers and forcing what was once a water-rich valley to import billions of gallons from far away.” That conveyance of water is so difficult, that many residents are unable to get water easily, especially from taps. This has led to an economy of ‘pipas’, “large trucks that deliver water from aquifers” to fill tanks. Approximately 40% of residents get water this way.

The other issue is the difficulty of removing sewage and drainage, again because of geology and topography, along with leaks and inefficiencies of the aged infrastructure. The Grand Canal is no longer able to gravity flow, described as “wide open, a stinking river of sewage belching methane and sulfuric acid”. Pump stations are installed to assist this, and the canal, albeit ‘visible’ is marginalized, traveling under roadways and being polluted via impervious surfaces along the way.

While portions of the Grand Canal are still visible, the hidden hydrology and it’s implications, heightened by climate change, are evident in sinking buildings, lack of drinking water, and substandard infrastructure, a trifecta of issues that come back to the origins of a water based city from seven centuries back. I mention long history, and this is a lesson in how quickly the decisions of the past can turn on us with population growth and a changing climate.

Per Kimmelman: “The whole city occupies what was once a network of lakes. In 1325, the Aztecs established their capital, Tenochtitlán, on an island. Over time, they expanded the city with landfill and planted crops on floating gardens called chinampas, plots of arable soil created from wattle and sediment. The lakes provided the Aztecs with a line of defense, the chinampas with sustenance. The idea: Live with nature.”

The idea at the time, and even today is valid, but the modern challenge is confirmed by Loreta Castro Reguera, “a young, Harvard-trained architect who has made a specialty of the sinking ground in Mexico City, a phenomenon known as subsidence” who was interviewed in the article.

““The Aztecs managed. But they had 300,000 people. We now have 21 million.”

Xochimilco

A follow up from features the further story of the hydrology of Xochimilco, a UNESCO World Heritage Site that was covered by Victoria Burnett in a February 22nd story “An Aquatic Paradise in Mexico, Pushed to the Edge of Extinction” This article picks up the thread of the canals and islands from the original settlement. “With their gray-green waters and blue herons, the canals and island farms of Xochimilco in southern Mexico City are all that remain of the extensive network of shimmering waterways that so awed Spanish invaders when they arrived here 500 years ago.”

The article focuses on the impacts of water usage in the region, with water from Xochimilco being pumped to other areas of the city, creating sink holes and draining canals which threaten the livelihoods of farmers and tourism industries. The canals have long supported both industries, and also include wetlands and the infamous farming techniques called chinampas, which date back to Aztec era, and include ‘floating gardens’ in the shallow lakes. A photo of these from 1912 show the this in action:

The article discusses the residual impacts of development on the aquifers, which impacts the regions waterways, but also, similar to the previous article, creates subsidence that impacts buildings and sinkholes. The visible whirlpool in January lowered the water level quick enough to cause alarm before it could be stopped.

The water tourism in the area, typified by the trajineras, a blinged out local gondola, has been impacted as well. One of the operators takes heed of the omens of water, stating:

“Nature is making us pay for what we have done”

In additional to development (building on the chinampas), there is pollution of the canals themselves, which has jump-started some efforts to reduce water use of the aquifer through rainwater harvesting, but the immensity of the problem of supplying water for a region with 22 million people is massive. The balance between providing water and maintaining the cultural heritage means the possible loss of knowledge of chinampa farming, as well as health issues for locals. This could quickly become irreversible, unless action is taken, as mentioned by Dr. María Guadalupe Figueroa, a biologist at Autonomous Metropolitan University, who ends the article: “…without a serious conservation effort, the canals will be gone in 10 to 15 years. But much of the damage was reversible, she said, adding: “It’s still a little paradise.”

Invisible Rivers

The two articles reminded me of a couple of articles I had filed away for future posts. With the interest piqued from the above coverage, I dove into a 2016 CityLab post “Mexico City’s Invisible Rivers” which focuses on the work of Taller 13 and their plans to “uncover the 45 rivers that flow under the Aztec capital, hidden underground for decades.” The first phase involves the Piedad River, and the idea of daylighting 9.3 miles of the corridor. shown in some detail below (with many more images on their site via the link above or via an online document here).

There’s a lot of similarity to the Cheonggyecheon River in Seoul (mentioned here in the Lost Rivers documentary post) in terms of the final look and feel as well as the transformative potential, as mentioned in the article by urban biologist Delfín Montañana”

““This project shatters paradigms. It proposes to tear down a private road, which you cannot use unless you have a car. What we propose is that we remove the cars, open the pipes, and treat the water. We need to transform the model of our city”

The hidden gem in the post is the document “La Ciudad de México 1952 1964” published by the Departamento del Distrito Federal. México, This document outlines the public services of the city, including chapters on water and sewer that have some great info (with, in my case, some translation).

Sections on potable water and drainage show ‘modernization’ along with maps of these systems (of passable by not great quality). The following shows the drainage system of the time, which involved a lot of pipes and images of pipes being built, and people in pipes.

A colored map of the historic Mexico from the document takes us full circle, to the hydrological history, a city literally built on a lake, economies as well built on that watery foundation, and now dealing with the consequences.

We live in an age where the impacts of climate change are seen daily. Data on global and local conditions is vital to our further understanding of adaptability and resilience both as protection from storms as well as mitigating longer term impacts. While understanding where we’re at in modern times is essential, comparing that to historical reference conditions connects threads from past to present and enlivens this discussion. Thus in the spirit of hidden hydrology and linkage to climate and rainfall, I was fascinated to learn about the book Climatology of the United States, And of the Temperate Latitudes of the North American Continent, authored by Lorin Blodget in 1857. This is interesting as it coincides with much of the development of Pacific Northwest cities in the mid 1850s so is a good indication of some predevelopment metrics, but more importantly is towards the beginning of the global Industrial Revolution (centered in London and radiating outwards), which led to rapid increase in development of industrial infrastructure and processes that created significant amounts of atmospheric CO2, which is arguably one of the biggest contributors to climate change.

This volume is 569 pages, packed full of info (and a massive PDF also). Most interesting to me and the original link i found was the amazing maps (abbreviated viewer here of the maps from the publication if you don’t want to download the whole thing) covering the world and specifically covering the temperate landscape of the Northern Hemisphere, with a focus on North America. In the introduction, some rationale for the project from Blodget.

I’m assumed he was referring to Alexander von Humboldt, but had missed the reference and probably would if he wouldn’t have mentioned it above. After some digging I noticed a deft reference in ‘The Humboldt Current: Nineteenth Century Exploration and the Roots of American Environmentalism’ (Aaron Sachs, 2007). Sachs links the two, mentioning on page 25-26, “Almost all American scientists in the mid-to-late nineteenth century, no matter what subfields they waded into, considered themselves disciples of Humboldt. One such author, Lorin Blodget, inserted a quote from the master himself on the title page of his own magnum opus, Climatology of the United States, to make a kind of textual frontispiece.”

The quote in small print on the front:

Like Humboldt’s work, the illustrations and summary visualizations of the phenomena he was describing, Climatology includes amazing illustrations (do yourself a favor and click the images in this post to enlarge them. The banner image of global temperatures above in the banner, as well as the world spanning ‘Comparison of Precipitation for the Temperate Latitudes of the Northern Hemisphere’ is Humboldtian indeed:

The smaller diagrammatic maps also evoke Humboldt’s stratification by elevation, captured in Blodget’s ‘Profile of the Altitudes’ for both the Pacific Coast of North America and the West Coast of Europe are some simple info-graphics rich in information and easily accessible.

The main substance of the document is the maps, include temperature (isothermal) and precipitation (hyetal) maps. There is a world view of both – as you’ve seen examples of above, but the focus is on North America, so each season is represented, along with an average annual. Summer and Winter are shown below, the difference being hopefully obvious:

The legend describes the map info, including max. and min. ranges for temps.

We take a lot for granted the amount of data, A challenge of the process was to gather and assimilate diverse information from a variety of sources, due to the fact that there was no consensus on the measurement and documentation of either temperature and rainfall data. Blodget spends a lot of time explaining the process, with a specific focus: “These references are deemed necessary to show that no part of the present work, whether supported by statistics and illustrators or not, was is the result of hasty or superficial discussion, and that all the steps of analytical investigation and detailed criticism required for such a purpose as that of constructing an approximate climatology, have been taken in advance.”

The rainfall maps are interesting as well showing in a variety of data, in shaded portions based on inches of rain. The image for annual totals shows the wetness of the southeast United States and the Pacific Northwest.

Zooming into the Southeast US – we see the intensity of rain in the southern tip of Florida, along with the Mississippi Delta. These are beautiful maps, considering they were done over 150 years ago, and the subtlety of shading and texture represented.

These are best represented in sequence (and i do love a good animation) so I did a quick overlay and made them step through seasons starting in Spring and sequencing through Summer, Autumn and Winter. Note the Pacific Northwest wet winter / dry summer cycle, and the overall difference between the coasts/interior as well as West Coast / East Coast. Somethings don’t change. Click to enlarge to make it a bit more legible.

I’ve yet to dive fully into the text, but have some context in the maps, and a curiosity to see the data at this level of analysis overlaid with modern information on isothermals and hyetals to show changes, in average and seasonal temps, changes in rainfall, and related hydrology and changes in things like plant hardiness ranges. Lots to unpack. While looking at this, I did find an earlier reference by Blodget, a slim volume published in 1853 which also tackles climate in reference to it’s impact on Sanitary conditions in cities, delving into the connections between climate and public health – well, 164 years ago.

The visual nature of the 1857 publication is not to be dismissed. The publisher J.B. Lippencott & Co., acknowledges the rarity of a book of this era having the size of quality plates, and their goal to make this available to the public at a reasonable cost. Such an interesting dilemma in our digital age, but one I’m glad for in terms of the production of this imagery as well as it’s preservation and archive. Just think, all this could have been yours in 1857 for the price of five dollars.

The climate data today… priceless.

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